<!doctype html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport"
        content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>Document</title>
  <style>
    .root{
      width: 100px;
      height: 100px;
      background-color: #c45353;
      margin-bottom: -20px;
    }
    .value{
      width: 100px;
      height: 100px;
      background-color: #2a9baf;
      opacity: 0.1;
    }
    .image {
      width: 100px;
      height: 100px;
      display: none;
      background-image: url("https://dimg04.c-ctrip.com/images/0zg15120008xs5j949E6F.jpg");
    }
  </style>
</head>
<body>

<div class="root">123</div>
<div class="value">456</div>
<div class="image"></div>
<script>
  function A() {
    this.b = 3;
  }
  var b = 5;
  var c = new A();
  A.prototype = {
    b: 7,
    d: 2,
  };
  // A.prototype.d = 2;
  A();

  console.log(b);
  console.log(c.b);
  console.log(c.d);
  console.log('分割线')
  Function.prototype.a = 10;
  function myFn() {

  }
  var fn = new myFn();
  console.log(fn.a);
  console.log(myFn.a);

</script>
</body>
</html>
